Printing ink for waxed pellets and process for applying the same



United States Patent 3,463,645 PRINTING INK FOR WAXED PELLETS AND PROCESS FOR APPLYING THE SAME John R. Kane, Ambler, Pa., assignor to Rex Laboratories, Inc., North Wales, Pa., a corporation of Pennsylvania No Drawing. Filed Nov. 2, 1966, Ser. No. 591,406

Int. Cl. C09d 11/08 US. Cl. 106-30 3 Claims ABSTRACT OF THE DISCLOSURE An edible ink for pharmaceutical tablets and the like. which is especially adapted to imprinting wax-coated pellets, the ink consisting essentially of a mixture of an edible shellac, an edible surfactant, alcohol, ammonia, an edible coloring agent, and water.

This invention relates to marking edible products or the like with an ink, and it particularly relates to marking pharmaceutical products such as capsules, tablets, and the like, hereinafter generally referred to as pellets, with an edible ink.

It is becoming increasingly important in the pharmaceutical and related industries to provide on the pellets themselves a ready identification of the manufacturer or other source of the goods. This is especially important in the case of the so-called prescription items which are usually sold to the customer in unmarked containers. Obviously, the ink used in marking the pellets must be readily edible and easily digestible. They must, however, also be substantially permanent and not likely to rub off because of friction between themselves in the container or because of handling.

The pellets used in the pharmaceutical industry are generally provided with a sugar coating that encapsulates the medicinal contents. This sugar coating itself usually has a smooth outer surface. However, heretofore, in order to apply the ink (which itself contains an edible shellac) to the pellets, it was necessary to apply a second or base coat of shellac to the pellets and then apply the ink to the shellac base coat. Due to the presence of shellac in both the ink and the base coat, the ink adhered tenaciously to the base coat and produced a highly satisfactory product. However, the shellac base had certain disadvantages. For one thing, the shellac gave a dull, lusterless appearance to the pellets. Even more important, it lacked free-sliding characteristics which interfered with many persons ability to swallow the pellets.

In order to provide the desirable luster and slipping qualities, many pharmaceutical manufacturers apply a wax coating (carnauba war or the like), over the sugar coated pellet. However, conventional shellac-based inks cannot easily print well or adhere to the wax coatings and are easily rubbed off.

An attempt to overcome the aforesaid disadvantages and to provide both a smooth, slippable surface and a permanent type marking was heretofore made, whereby the sugar coated pellet was coated with a wax, that was then rubbed or polished to a smooth finish, and then imprinted with an ink consisting essentially of so-called confectioners glaze, cyclohexane, ammonia and a coloring agent. This process did provide a great improvement in both slipping qualities and marking stability. However, not only was there still some tendency of the ink to rub off, but if required the use of relatively large amounts of ammonia and cyclohexane, both of which have pungent, obnoxious, irritating odors. Furthermore, ammonia is lethal at relatively low concentrations while cyclohexane is highly flammable and is also lethal, but at higher concentrations than the ammonia. This made the manu facture of these inks quite expensive because of the great care required in the use of these materials. It was also undesirable to use such materials in the relatively large proportions required for effectively making pellets which were destined for human use.

It is, therefore, an object of this invention to overcome all the disadvantages heretofore encountered in this field by providing an ink and a process of using it whereby a pellet is obtained that has both high slippability and substantially permanent marking, but which utilizes a minimum of inherently toxic or dangerous materials.

Another object of the present invention is to provide an ink and process of the aforesaid type which reduce both the complexity and cost of manufacture and use.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description and claims.

In accordance with the present invention, an ink is prepared utilizing only a small amount of ammonia and no cyclohexane at all. Instead, certain surfactants and water are incorporated into the composition. These form an emulsion with the wax and penetrates through the wax coating to reach the surface of the sugar coating. These surfactants are not toxic and not dangerous to use. Nevertheless, they perform the same function as the combination of the cyclohexane and ammonia, but in an even more efficient and effective manner. They are not only readily available but inexpensive and easy to use, and, therefore, substantially cut the cost of produc tion. The water should be present in a maximum amount consistent with rapid drying.

The following examples illustrate the invention. However, they are not intended to limit the invention except as claimed:

Example 1 Components: Parts by wt. Confectioners glaze (8 lb. cut) 42.000 Ammonia (26 Baum) 1.35'0 Distilled water 19.650 Titanium dioxide (purified) 30.000 Isopropyl alcohol (anhydrous) 6.730

Span 60 (sorbitan manostearate produced by Atlas Chemical Industries, Inc., Wilmington, Del.) 0.135 Tween 20' (polyoxythylene sorbitan monolaurate produced by Atlas Chemical Industries, Inc., Wilmington, Del.) 0.135 Talc (U.S.P.) 3.500

The confectioners glaze is a purified edible shellac, that is free of arsenic and lead as well as wax, and is of the type generally used in inks for this purpose. The alcohol is used to control the rate of evaporation of the ink so as to keep it liquid enough to give it sufiicient time to pentrate through the wax, but not long enough to flow into surrounding areas. The talc is used to increase the slippability of the pellets and to prevent the ink film from being flaked-01f as the result of vibration and friction during handling and shipping.

The purity of all the components listed above must be such as to be fit for human consumption and approved by the US. Food and Drug Administration.

The various components listed above are mixed, at room temperature and pressure, to produce the finished ink, which is white in color.

Example 2 Components: Parts by wt. Confectioners glaze (8 lb. cut) 54.000 Ammonia (26 Baum) 1.500 Distilled water 25.500 Isopropyl alcohol (anhydrous) 8.230 Carbon black (purified) 3.500 D&C Blue #6 3.500 Talc (U.S.P.) 3.500 Span 60 0.135 Tween 20 0.135

The above components are mixed at room temperature and pressure to provide a black ink.

These components are mixed at room temperature and pressure to obtain a red ink.

Example 4 Components: Parts by wt. Confectioners glaze (8 lb. cut) 48.750 Ammonia (26 Baum) 1.250 Distilled water 22.750 Isopropyl alcohol (anhydrous) 8.000 FDC Yellow 5 Lake 6.000 FDC Blue 1 Lake 6.000 Titanium dioxide (purified) 4.000 Talc (U.S.P) 3.000 Span 60 0.125 Tween 0.125

These components were mixed at room temperature and pressure to obtain a green ink.

Although Span 6'0 and Tween 20 have been used here for specific illustration, other edible non-ionic surfactants may be substituted.

In the printing of sugar coated, waxed pellets, the ink may be applied in any manner known to the art, as, for example, by means of a pellet printing machine. After the printing operation, the pellet is dried for a period of time suflicient to provide the desired degree or hardness.

If desired, the drying may be accelerated by the application of limited amounts of heat.

The proportions of the various components may, of course, be somewhat varied. For example, the shellac may be present in a proportion of about 32 to parts by Weight, the talc in about 2.0 to 8.0 parts by weight, the surfactants in about 0.1 to 1.2 parts by weight, or 0.05 to 0.6 part by weight of each when two are used as in the examples above, the ammonia in about 0.95 to 2.5 parts by weight, the water in about 15.0 to 28.5 parts by weight, the alcohol (which may be ethyl or any other edible alcohol as well as isopropyl) in about 3.0 to 12.0 parts by weight, and the coloring agents in any desired proportion depending on their printability and desired deepness of shade.

Although this invention has been described with relation to pharmaceutical pellets, it has equal application to inks used for other purposes such as foods, cosmetics or even toys that are apt to be sucked on by children.

Obviously, many modifications of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

The invention claimed is:

1. In a method of imprinting an object, the steps which comprise coating the surface of the object with an edible wax and then imprinting the wax-coated object with a non-toxic printing ink consisting essentially of about 32 to 65 parts by weight of an edible shellac, about 0.95 to 2.5 parts by weight of ammonia (26 Baum), about 0.1 to 1.2 parts by weight of an edible, non-ionic surfactant, about 3.0 to 12.0 parts by weight of an alcohol selected from the group consisting of ethyl alcohol and isopropyl alcohol, about 15.0 to 28.5 parts by weight water, and a sufficient amount of a coloring agent to obtain a desired degree of deepness of shade.

2. The method of claim 1 wherein the object is a pharmaceutically acceptable pellet having a sugar coating beneath the wax coating.

3. A non-toxic printing ink consisting essentially of about 32 to 65 parts by weight of an edible shellac, about 0.95 to 2.5 parts by weight of ammonia (26 Baum), about 0.1 to 1.2 parts by weight of an edible, non-ionic surfactant, about 3.0 to 12.0 parts by weight of an alcohol selected from the group consisting of ethyl alcohol and isopropyl alcohol, about 15.0 to 28.5 parts by weight water, and a sufficient amount of a coloring agent to obtain a desired degree of deepness of shade.

References Cited UNITED STATES PATENTS 2,948,626 8/ 1960 Sanders 106-30 XR 2,982,234 5/1961 Ackley et al. 3,258,347 6/1966 Brown 106-30 3,297,535 1/ 1967 Butler et al. 3,173,839 3/1965 Nicholson.

JULIUS FROME, Primary Examiner J. B. EVANS, Assistant Examiner US. Cl. X.R. 

